It's pretty straightforward. I built a circuit to energize a coil and connected a diode in parallel to make sure the discharge won't harm the transistor. The diode is in working order, I've tested it with a multimeter and found that it has a high resistor value when forward-biased and it doesn't conduct when reverse-biased. Now, if I connect the diode to the coil (and nothing else, I don't even connect the battery) and proceed to measure the resistance value across the diode, I find that the value is the same for forward-biased and reverse-biased and it's around 0.04 ohm (as if the diode were acting like a conductor). This would explain why I found no voltage differential on the terminals of the coil when I connected the battery, but I am at a loss to explain why this happens. I simulated the circuit using NI Multisim and it works like a charm. Can anybody tell me what I'm doing wrong?